TY - JOUR
T1 - Effects of thermal hydrolysis process-generated melanoidins on partial nitritation/anammox in full-scale installations treating waste activated sludge
AU - Pavez-Jara, Javier A.
AU - van Lier, Jules B.
AU - de Kreuk, Merle K.
PY - 2023
Y1 - 2023
N2 - Thermal hydrolysis process (THP) is a well-established anaerobic digestion (AD) pre-treatment technology. Despite the THP benefits the pre-treatment increases the concentrations of nutrients and melanoidins in the digestate reject water after dewatering. The increased concentrations of nutrients and melanoidins formed during THP-AD can impact downstream processes, such as struvite precipitation and partial nitritation/anammox (PN/A). In our present work, six full-scale PN/A influents and effluents were sampled in The Netherlands (4 with THP and 2 without THP). Full-scale samples were characterised and the stoichiometric O2 consumption and melanoidins chelated to trace elements were analysed. The results showed that THP increased the concentration of total ammoniacal nitrogen (TAN), chemical oxygen demand (COD), total organic carbon (TOC), UVA 254 and colour, which are indicators of melanoidins occurrence. THP furthermore decreased the stoichiometric NO3−-N production from the PN/A reaction in effluents. The disparity between stoichiometric and measured NO3− -N in the THP-using plants was explained by the proliferation of denitrifiers. Moreover, denitrification improved the N removal efficiency due to the consumption of the stoichiometrically-produced NO3− -N. Also, the stoichiometric O2 consumption increased in the plants using THP, reaching up to 56% of the O2 used for partial oxidation of TAN. Trace elements analysis revealed that the plants with elevated concentrations of melanoidins in the effluent showed a high percentage of chelated multivalent cations, particularly transition metals such as Fe. Kendall correlation coefficient analysis showed that the chelation of multivalent cations was correlated mainly with colour occurrence in the reject waters. Overall, the results indicated that in PN/A systems using THP-AD increased O2 consumption and trace elements availability should be considered during the process design.
AB - Thermal hydrolysis process (THP) is a well-established anaerobic digestion (AD) pre-treatment technology. Despite the THP benefits the pre-treatment increases the concentrations of nutrients and melanoidins in the digestate reject water after dewatering. The increased concentrations of nutrients and melanoidins formed during THP-AD can impact downstream processes, such as struvite precipitation and partial nitritation/anammox (PN/A). In our present work, six full-scale PN/A influents and effluents were sampled in The Netherlands (4 with THP and 2 without THP). Full-scale samples were characterised and the stoichiometric O2 consumption and melanoidins chelated to trace elements were analysed. The results showed that THP increased the concentration of total ammoniacal nitrogen (TAN), chemical oxygen demand (COD), total organic carbon (TOC), UVA 254 and colour, which are indicators of melanoidins occurrence. THP furthermore decreased the stoichiometric NO3−-N production from the PN/A reaction in effluents. The disparity between stoichiometric and measured NO3− -N in the THP-using plants was explained by the proliferation of denitrifiers. Moreover, denitrification improved the N removal efficiency due to the consumption of the stoichiometrically-produced NO3− -N. Also, the stoichiometric O2 consumption increased in the plants using THP, reaching up to 56% of the O2 used for partial oxidation of TAN. Trace elements analysis revealed that the plants with elevated concentrations of melanoidins in the effluent showed a high percentage of chelated multivalent cations, particularly transition metals such as Fe. Kendall correlation coefficient analysis showed that the chelation of multivalent cations was correlated mainly with colour occurrence in the reject waters. Overall, the results indicated that in PN/A systems using THP-AD increased O2 consumption and trace elements availability should be considered during the process design.
KW - Ammonium oxidising organisms
KW - Anammox
KW - Complexation
KW - Humic substances
KW - Melanoidins
KW - Thermal hydrolysis process
UR - http://www.scopus.com/inward/record.url?scp=85177888067&partnerID=8YFLogxK
U2 - 10.1016/j.jclepro.2023.139767
DO - 10.1016/j.jclepro.2023.139767
M3 - Article
AN - SCOPUS:85177888067
SN - 0959-6526
VL - 432
JO - Journal of Cleaner Production
JF - Journal of Cleaner Production
M1 - 139767
ER -
